The grid is a useful device for expressing design rules about the placement of elements in a layout. By expressing position rules for elements in relation to a grid, a designer can systematically organize decisions in a layout design problem. Grids and placement rules offer a discipline that can help a designer work effectively to lay out complex designs, and it can also facilitate group design work. Unfortunately, computer supported drawing systems often cannot support this way of working because they lack a sufficiently rich implementation of grids. The Grid Manager module of the CoDraw program shows enhancements useful for architectural Computer Assisted Design. These enhancements would enable more effective ways of using the computer as a design tool.